Digestive System Lesson Plan Grade 12

Digestive System

Lesson Plan

Grade 12

Elisabeth Ormandy, 2020.

Do not make copies and/or distribute the material contained in this document without

explicit, written permission.

TABLE OF CONTENTS

Curriculum alignment............................................................................. 4

Curriculum competencies & recommended tools........................... 5

Lesson plan overview............................................................................. 6

Lesson plan approach............................................................................. 7

Detailed lesson content & teaching notes......................................... 8

Digestive system major structures...................................................... 9

Food flow through the body................................................................ 11

Stomach anatomy................................................................................... 17

Pancreas anatomy.................................................................................. 19

Villi anatomy nutrient breakdown...................................................... 21

Interdependence of digestive and other organ systems............... 22

Hepatic portal system............................................................................ 24

The digestive system & homeostasis................................................. 25

Common digestive diseases................................................................. 27

Closing check-in & discussion.............................................................. 28

Elisabeth Ormandy, 2020.

Structure and function

Structural and functional interdependence

Maintenance of homeostasis

The following unit plan was created in accordance with the Canadian Council on

Animal Care’s recommendations to replace any present procedures involving the

use of animals in teaching, testing and research.

The Three Rs principle of Replacement states, if you can meet your scientific or

educational goals without the use of animals, it is your ethical obligation to use non-

animal methods. Grade 12 anatomy content is often taught using fetal pigs - here

we offer an effective and humane alternative.

This is in alignment with the public’s concern for animal welfare and a cultural

respect for animals passed down from the Aboriginal perspectives of the First

Peoples.

Elisabeth Ormandy created this unit plan and series of lesson plans for your use in

teaching life science content to Grades 12 based on the BC Science Curriculum.

These Humane Science Education materials were developed to provide equivalent

or greater standards in education for Canadian youth, without the use of animals.

Curriculum Alignment

This lesson plan can be used to create classes for Grades 12 based on the BC

Science Curriculum. Specific Big Ideas covered in this lesson plan include:

Grade 12 - Organ systems have complex interrelationships to maintain homeostasis.

ORGAN SYSTEMS:

We have recommended specific virtual anatomy tools to use to get the most out of

the lesson plan. You'll find links to those on pages 5&6.

Elisabeth Ormandy, 2020.

Lesson Plan Overview

Subject: Science

Unit Overview: Anatomy and Physiology

Unit Duration: ~90 minutes

Grade: 12

Big Idea: Organ systems have complex interrelationships to maintain homeostasis

Curricular Competencies

Analyze cause-and-effect relationships

Construct, analyze, and interpret graphs, models, and/or diagrams

Consider the changes in knowledge over time as tools and technologies have developed

Content

By the end of this lesson, students are expected to demonstrate understanding of

the following:

Digestive system:

Structure and function

Structural and functional interdependence

Maintenance of homeostasis

6 (or more) iPads or other tablets

6 (or more) 3D Anatomica workbooks

3D Anatomica:

https://3danatomica.com

3D4Medical Complete Anatomy: https://3d4medical.com

Hardware & Workbooks:

This inventory is for a regular in-person class - use x1 iPad/tablet per student for

responsible physical distancing. If teaching online, teachers can screen share their

iPad/tablet or desktop.

Recommended Software:

Recommended Education Tools

Elisabeth Ormandy, 2020.

Lesson Plan Overview

Topic: Organ systems have complex interrelationships to maintain homeostasis.

Homeostasis is maintained through physiological processes.

Content: The human digestive system: organs, structure and function

Goals

Objectives

Materials

Introduction

Development

Practice

Describe the function of the digestive system and its major organs.

Describe the relationships between the different components of the

digestive system.

Explain how the digestive system is interdependent with the

circulatory system.

Explain how the digestive system maintains homeostasis in the body.

Students will be able to:

After this lesson students will state the structure and function of each

organ/tissue in the digestive system and explain how the digestive

system is functionally interdependent with other body systems.

3DAnatomica

3D4Medical

Digestive System Workbook

Using the 3DAnatomica and/or 3D4Medical app(s), the teacher will

introduce the topic of cardiovascular organ structure and function.

What is the advantage of having specialized tissues in the digestive

system?

How does the digestive system help the body maintain internal

balance during exercise?

What are the impacts of external stimulants (e.g. alcohol, caffeine) on

the digestive system?

What lifestyle decisions would you make to improve your digestive

health?

How does the digestive system respond to infection by a pathogen?

Questions to support inquiry-based learning:

Students will work independently or in pairs to navigate 3DAnatomica

and/or 3D4Medical to learn about the structure and function of the

digestive organs.

Elisabeth Ormandy, 2020.

Split students into 6 groups.

Give each group a Digestive System workbook to refer to, and one (or more)

iPad(s) or tablet(s) with the 3D Anatomica app, and 3D4Medical Complete

Anatomy app loaded and ready to use.

Your introduction should include discussion of the function of the digestive

system, identifying its major components, and the vocabulary you would like

students to learn (~ 15 mins). Define homeostasis. Have the students follow along

using the 3D4Medical Complete Anatomy app.

Have students label "Major Structures" diagram on page 10 using 3D4 Medical.

Discuss sequence of organs and structures that food moves through within the

digestive system. Have students use the 3D Anatomica and 3D4Medical Complete

Anatomy app to explore the flow of food in their groups, filling their 3D Anatomica

workbook and/or handouts provided. This can be student or teacher led (40-45

mins).

Explore the "Structures in Detail" pages using the 3D4 Medical App. The students

can cut away at the structures in the app to locate structures that need to be

labeled.

Ask students to brainstorm ways the digestive system interacts with other

systems, and go over the specific examples provided

Discuss different ways the digestive system helps maintain homeostasis using

examples provided, then ask students to provide their own examples using what

they've learned.

Close the class with a 20-minute recap of what the students have learned, discuss

how the parts of the digestive system work together, and check for understanding.

Begin a conversation on ethics of animals in science using the questions provided.

Use x1 iPad for each student and proceed as per the directions above.

Lead the students through the digestive system by screen sharing your own

iPad/tablet or desktop with the 3D4Medical Complete Anatomy app installed,

filling out the tables, and labeling the models as you go.

Proceed as per the directions above.

If teaching regular in-person classes:

If teaching a physically-distanced class:

If teaching online:

Lesson Plan Approach

Elisabeth Ormandy, 2020.

Introduction to the Lesson

Include a First Nations land acknowledgement and ask students to reflect on what

respect for animals means to them. Provide an introduction to the apps and models

that will be used in class. Provide an overview of how to access 3D Anatomica

workbooks if teaching remotely.

What is Homeostasis? Discuss with Students

In biology, homeostasis refers to the body’s ability to maintain a stable internal

environment despite changes in external conditions.

Introduction to the Topic

Students will use the 3D4Medical Complete Anatomy app to explore the digestive

system at large. We recommend covering the function of the digestive system,

identifying the major components of the system, and discussing the vocabulary you

would like the students to learn early in the lesson.

Detailed Lesson Content & Teaching Notes

THE DIGESTIVE SYSTEM AT-A-GLANCE

Function

Components

Important vocabulary

The digestive system is responsible for taking whole foods and

turning them into nutrients and energy, which allows the body to

function, grow and repair itself.

Mouth, esophagus, stomach, small intestine, large intestine, rectum,

liver, pancreas, gallbladder.

Homeostasis, mouth, salivary glands, salivary amylase, palate,

esophagus, pharynx, epiglottis, esophageal sphincter, bolus,

peristalsis, stomach, chyme, mucus cells, parietal cells, peptic cells,

pepsin, HCl, peptides, pyloric sphincter, pancreas, mesenteric vessels,

exocrine, endocrine, pancreatic duct, alkaline, neutralize, basic,

amylase, peptidases, lipases, nucleases, glycogen, glucose, secretin,

gallbladder, bile, bile duct, small intestine, enzymatic hydrolysis,

duodenum, jejunum, ileum, villi, microvilli, cytoplasmic, amino acids,

lipoproteins, large intestine, cecum, iliac crest, appendix, ascending

colon, transverse colon, descending colon, rectum, feces, anus, liver.

Elisabeth Ormandy, 2020.

Digestive System Major Structures

(Teacher Copy)

Liver

Gallbladder

Pancreas

Duodenum

Esophagus

Stomach

Tranvserse

Colon

Jejunum

Descending

Colon

Rectum

Anus

Colon

Ileum

Ascending

Colon

Elisabeth Ormandy, 2020.

Digestive System Major Structures (Student Copy)

Elisabeth Ormandy, 2020.

Digestive System Food Flow (Teacher Copy)

Explore the path food moves through within the digestive system, noting the function

and structure of each major organ, using the apps provided, and fill out your workbook.

Order Organ Structure, function & information

Esophagus

Mouth

Stomach

Mechanical Digestion: chewing

Chemical Digestion: saliva breaks down carbohydrates/starches

2 Types of Digestion:

3 sets of salivary glands produce saliva to lubricate and break down the food.

Teeth: mix of canines and molars to masticate (tear/bite/grind/crush) the food into

smaller pieces.

Tongue: muscular organ that mixes the food with saliva and aids with swallowing.

Salivary Amylase: enzymes that digest the carbohydrates in the mouth.

Palate: forms the roof of the mouth.

From the mouth, food passes through the pharynx (5-6 inches long).

During swallowing, the sphincter muscles relax and raise the epiglottis, which

prevents the bolus from entering the trachea.

After bolus leaves pharynx, it enters the esophagus.

Peristalsis: contractions of the esophagus that move food bolus along in a wave

like motion.

Esophageal sphincter: separates esophagus from the stomach to prevent food

reflux.

Thick-walled, J-shaped organ, lies on left side of body, under diaphragm.

Stores food and mixes it with gastric juice.

Bolus enters the stomach, then is converted to semi-fluid, partially digested food called

chyme.

Stomach contents are extremely acidic (pH b/w 1.5-2.5).

Acidity breaks down food tissues, kills microorganisms & activates digestive enzymes.

3 layers of muscles churn and mix contents by contracting.

Pacemaker cells stimulate stomach contractions, which increase in number the fuller

the stomach.

Hunger pains= churning of an empty stomach.

Mucus lining of stomach contains inner gastric juice producing gastric glands.

Stomach empties into the first part of the small intestine (duodenum).

Pyloric sphincter at the bottom of the stomach controls this emptying.

Elisabeth Ormandy, 2020.

3.2

3.1

Pancreas

Gallbladder

Small

Intestine (SI)

Acinar Cells - secrete digestive juices which travel through pancreatic duct to

small intestine

Islets of Langerhans: secrete insulin and glucagon into blood

Location: just below the stomach

Two types of tissues:

Connections:

Plentiful blood supply through mesenteric vessels.

Mesentery connective tissue holds it in place.

Pancreatic and common duct connect it to the small intestine.

Pancreas supplies digestive enzymes to break down:

lipids (fats) into glycerol and fatty acids,

carbohydrates into glucose,

proteins into amino acids.

These are released into the duodenum via the pancreatic duct.

Stores bile produced in the liver, which is released into the duodenum via the bile

duct. Breaks down fatty contents of food.

Duodenum - 25-30 cm long, receives food from stomach, receives bile &

pancreatic juice through common duct. Site of most active enzyme production

and digestion.

Jejunum - 1-1.5 m long, fewer intestinal glands, more specialized for absorption.

Ileum - 4-5 m long, produces no enzymes, but does most of the absorption of

nutrients not taken up by jejunum or duodenum.

Site of most enzymatic hydrolysis of food and absorption of nutrients (~ 6m in

length).

Made up of 3 major sections:

Large surface area of SI results from several levels of folding:

Circular folds in submucosa slow passage of food and increase the area. Covered

with villi - finger-like microscopic projections, which themselves are covered with

microvilli - tiny cytoplasmic projections from the surface of individual columnar

epithelial cells. Capillaries wrap around villi to absorb nutrients.

SI Function: neutralize acidity of the acid stomach contents with bicarbonate from

pancreas.

Mechanically mixes chyme w/pancreatic juice, bile and intestinal secretions to

continue breakdown of food. Absorbs simple sugars and amino acids into blood by

active transport (requires ATP). Absorbs fatty acids and glycerol, reassembles into

new fat molecules, coats them with lipoproteins and cholesterol and sends them into

the lymph system.

Blood vessels from villi in SI merge to form hepatic portal vein (which leads to liver).

Elisabeth Ormandy, 2020.

Large

Intestine (LI)

Liver

Ascending colon: rises up right side of the abdomen

Transverse colon: crosses top of abdomen

Descending colon: goes down left side where it joins the

Rectum

Size: 1.5m long. Joins w/ SI near iliac crest, in the lower right corner of abdomen.

The caecum is the name given to the blind end of the LI. Appendix projects from the

caecum.

LI has 4 major parts:

Feces are formed from indigestible food, excreted materials and bacterial cells. Feces

leave through the anus. Anus normally held closed by internal (smooth) and external

(skeletal) anal sphincters.

Functions:

Peristalsis - mechanical movement moves feces along.

Absorption - some salts and water absorbed from feces.

Bacteria (E.coli) work on undigested food from the SI and produce gases (flatulence,

about 1.5L/day), amino acids and some vitamins.

The intestinal lining absorbs the amino acids and vitamins produced.

Unlike the SI, the LI does NOT have villi.

Produces bile that breaks down (emulsifies) fats into small droplets, but large

enough surface area for pancreatic lipase to work on. Bile is stored in

gallbladder. Bile is green b/c it contains broken down hemoglobin pigments

from liver.

Converts glucose to glycogen post meal, then in the hours between meals, back

to glucose.

Maintains blood sugar levels under control of pancreatic hormones.

Interconverts carbs to fats, and amino acids to carbs and fats.

Converts hemoglobin (from old blood cells) into bilirubin, pigments which give

bile its colour.

Produces blood proteins, like albumin. These proteins regulate the osmotic

balance of blood and fibrinogen (aids in blood clotting).

Breaks down and detoxifies: blood circulating hormones, alcohol, some

antibiotics, many drugs, and toxins found in some foods.

Stores iron and vitamins.

Makes cholesterol.

Location: on the right side of the body, under the ribs, below the diaphragm.

Size: 2 lobes, roughly triangular, ~1.5 kg.

Connections: all blood from the intestines travels through the hepatic portal vein

and arrives at the liver.

Functions:

Elisabeth Ormandy, 2020.

Order Organ Structure, function & information

Esophagus

Mouth

Stomach

Digestive System Food Flow (Student Copy)

Explore the path food moves through within the digestive system, noting the function

and structure of each major organ, using the apps provided.

Elisabeth Ormandy, 2020.

3.2

3.1

Pancreas

Gallbladder

Small

Intestine (SI)

Elisabeth Ormandy, 2020.

Large

Intestine (LI)

Liver

Elisabeth Ormandy, 2020.

Gastric Folds

Duodenum

Esophagus

Components in Detail:

Stomach Anatomy (Teacher Copy)

A mucus layer prevents

the HCl from eating

through

Pepsin could digest

protein in the stomach

cells, but pepsin is

inactive until it mixes

with HCl

HCl isn't formed until it

crosses the stomach

lining

Why doesn't the stomach

digest itself?

Cardiac Sphincter

Pyloric

Sphincter

Mucus cells: secrete protective coat

Parietal cells: secrete HCl (pH 3) which kill bacteria and help

breakdown food

Peptic cells: secrete pepsinogen, which forms the enzyme pepsin

when combined with HCl. Pepsin is a hydrolytic enzyme that breaks

down proteins into smaller amino acid chains called peptides

Peptides are broken down into individual amino acids further on in

digestive system by other enzymes

There are 3 types of stomach cells:

Protein + H2O --- Pepsin ---> Peptides

Elisabeth Ormandy, 2020.

Components in Detail:

Stomach Anatomy (Student Copy)

Why doesn't the stomach

digest itself?

Mucus cells: secrete protective coat

Parietal cells: secrete HCl (pH 3) which kill bacteria and help

breakdown food

Peptic cells: secrete pepsinogen, which forms the enzyme pepsin

when combined with HCl. Pepsin is a hydrolytic enzyme that breaks

down proteins into smaller amino acid chains called peptides

Peptides are broken down into individual amino acids further on in

digestive system by other enzymes

There are 3 types of stomach cells:

Protein + H2O --- ---> Peptides

Elisabeth Ormandy, 2020.

Common Bile Duct

Duodenum

Produces insulin: controls cellular

uptake of glucose and its

conversion into glycogen (insulin

secreted when low glucose levels in

blood).

Produces glucagon: stimulates

conversion of glycogen into glucose

(glucagon secreted when high

glucose levels detected in blood)

This regulates blood sugar.

Endocrine Functions: cell secretions

released into blood

Produces bicarbonate ions (HCO3).

These neutralize stomach acids and

make pH of intestine 7-8 (alkaline).

released through pancreatic duct.

Small intestine enzymes are

optimum at basic pH

Produces digestive enzymes: amylases,

peptidases, lipases, and nucleases

released through pancreatic duct

into the small intestine

Exocrine Functions: cell secretions are

released into a duct

Components in Detail:

Pancreas (Teacher Copy)

Pancreatic Duct

Gallbladder

Common Hepatic Duct

Just after eating high glucose level

food, insulin is secreted which

causes cells to take up glucose in

the liver and muscle. Glucose is

then converted into glycogen for

storage. When fasting, glucagon

converts glycogen in the liver and

muscle into glucose

Elisabeth Ormandy, 2020.

Produces insulin: controls cellular

uptake of glucose and its

conversion into glycogen (insulin

secreted when low glucose levels in

blood).

Produces glucagon: stimulates

conversion of glycogen into glucose

(glucagon secreted when high

glucose levels detected in blood)

This regulates blood sugar.

Endocrine Functions: cell secretions

released into blood

Produces bicarbonate ions (HCO3).

These neutralize stomach acids and

make pH of intestine 7-8 (alkaline).

released through pancreatic duct.

Small intestine enzymes are

optimum at basic pH

Produces digestive enzymes: amylases,

peptidases, lipases, and nucleases

released through pancreatic duct

into the small intestine

Exocrine Functions: cell secretions are

released into a duct

Components in Detail:

Pancreas (Student Copy)

Just after eating high glucose level

food, insulin is secreted which

causes cells to take up glucose in

the liver and muscle. Glucose is

then converted into glycogen for

storage. When fasting, glucagon

converts glycogen in the liver and

muscle into glucose

Elisabeth Ormandy, 2020.

Complex

Carbohydrates

(starch)

Proteins

Fats

Nucleic Acids

Amylases

Pepsin

Trypsin

Cholesterol + Bile

Salts

Nucleases

Disaccharides

(maltose, lactose)

Short

polypeptides

Emulsified Fat

droplets

Phosphates,

sugars, and bases

Maltase

Lactase

Peptidases

Lipases

Glucose

Amino Acids

Fatty acids +

Glycerol

absorb amino acids

and glucose, and

carry them back to

the hepatic portal

vein, liver and

mesenteric vessels

Components in Detail:

Villi and Nutrient Breakdown

Epithelial cells

Blood Capillaries

Lacteal

Nutrient Breakdown

Lymph vessel

that returns

lipoprotein

droplets and fluid

to bloodstream

microvilli for

absorption

glandular cells

produce and

release

enzymes/mucus

into intestinal

lumen

some have

digestive enzymes

bound to their

outer membrane

Outer layer of villi

one cell thick to

increase rate of

diffusion.

Can be covered in

various types of cells

with different

functions:

Elisabeth Ormandy, 2020.

How Does the Digestive System Work Together With Other

Organ Systems? (Teacher Copy)

Ask students how they think the different organ systems work together based on what they've

learned so far – specific questions can include:

1. How does the integumentary and digestive system interact?

2. How does the muscular system aid in digestion?

3. Does the digestive system produce any hormones ? How do they interact with the body?

4. What does the Hepatic Portal System have to do with the digestive and cardiovascular

system?

Integumentary System

The skin provides vitamin D, which plays an integral role in the

absorption of vitamin C in the digestive tract, and helps protect the

digestive tract. The digestive system provides nutrients required by skin,

hair, and nails.

Muscular System

Peristalsis is created by smooth muscles, while skeletal muscles aid in

voluntary sphincter control, swallowing, and protect and support

abdominal organs. The digestive system provides cellular energy (ATP),

which is required by muscular cells, from micro-nutrients produced in the

digestive tract. Lactic acid build up after muscle activity is metabolised by

the liver.

Endocrine System

Endocrine hormones aid in secretion regulation in accessory organs and

digestive glands; glucose storage in the liver is controlled by insulin and

glucagon. Hormones are also produced by the small intestine and

stomach.

Cardiovascular System

Blood vessels transport nutrients from the digestive system to various

other parts of the body. Nutrients from the digestive system are

provided for the formation of blood cells and plasma protein. Plasma

proteins are produced by the liver. It also destroys old red blood cells and

detoxifies blood.

Elisabeth Ormandy, 2020.

How Does the Digestive System Work Together With Other

Organ Systems? (Student Copy)

How does the integumentary and digestive system interact?

How does the muscular system aid in digestion?

Does the digestive system produce any hormones ? How do they interact with the body?

What does the Hepatic Portal System have to do with the digestive and cardiovascular

system?

Ask students how they think the different organ systems work together based on what they've

learned so far – specific questions can include:

Integumentary System

Muscular System

Endocrine System

Cardiovascular System

Elisabeth Ormandy, 2020.

Hepatic Portal System:

Cardiovascular and Digestive System Interdependence

Hepatic portal vein: This is the main vein connected to the liver. It forms at the

connection of the inferior and superior mesenteric veins.

Inferior mesenteric vein: This vein takes blood from the colon and rectum and connects

with the portal vein.Superior mesenteric vein: This drains blood from the small intestine

and connects with the hepatic portal vein.

Gastrosplenic vein: This tributary is formed by the union of the splenic vein from the

spleen and the gastric vein from the stomach. It joins with the mesenteric vein inside the

pancreas.

The hepatic portal system is a series of veins that carry blood from the capillaries of the

stomach, intestine, spleen, and pancreas to capillaries in the liver. It is part of the body’s

filtration system. Its main function is to deliver de-oxygenated blood to the liver to be

detoxified further before it returns to the heart.

The hepatic portal system consists of:

The hepatic portal system is designed to rid the body of toxins, and it cannot detect those

that are designed to help it. Some drugs must be taken under the tongue, through the skin,

or via suppository to avoid entering the hepatic portal system and being prematurely

metabolized in the liver before reaching general circulation.

Inferior vena cava

Capillary bed in liver

Hepatic veins

Liver

Stomach

Large intestine

Capillary bed in intestine

Small intestine

Step 4: Hepatic veins

deliver blood to the

circulatory system

Step 3: The liver

monitors blood

contents.

Step 2: Digested food

molecules then travel

through hepatic portal

vein to the liver

Step 1: Products of

digestion are absorbed

into the capillaries

within the villi of the

small intestine

Elisabeth Ormandy, 2020.

How Does the Digestive System Help Maintain Homeostasis?

To keep the internal environment in the body functioning properly, maintaining homeostasis is required.

The digestive system, along with other body systems, help maintain energy homeostasis.

Provide Nutrients

For all systems to work properly, the body needs macro and micro-nutrients. Chemical and mechanical

digestion break down ingested food to gain access to these nutrients. This begins in the mouth, where

food is mixed with enzymes and saliva, and continues as it enters the stomach, where it is mixed and

gastric juices and churned into chyme. The stomach also produces several hormones that regulate

digestion of food. Once the chyme enters the small intestine, it is further digested by bacteria.

Nutrients are absorbed by the small intestine, with some further absorption of water occurring in the

large intestine.

Bacterial flora located in the intestine are essential in the role of homeostasis. They both allow for

nutrient absorption by breaking down the food, and produce vitamins such as biotin and vitamin K,

which help protect harmful bacteria from entering the system.

Digestive Organs

The bile salts manufactured by the liver that enter the intestines help emulsify fats, simplifying their

absorption and digestion process. The liver is a vital player in the role of homeostasis. It breaks down

alcohol, drugs, and other toxic substances. It stores glucose as glycogen after meals, and produces

plasma proteins. In between meals, it releases glucose to keep the concentration of blood glucose

constant, regulating the body’s blood sugar.

What are some other examples of the digestive systems ability to

maintain homeostasis within the body?

Elisabeth Ormandy, 2020.

To transfer nutrients to the internal environment from the external environment

Provides energy required by cell processes according to individual needs, these molecules

must constantly be replaced

Avoids losses to body proteins by maintaining a positive nitrogen balance

Provides vitamins and nutrients that cannot be synthesized by cells, e.g. essential amino

acids/fatty acids

Maintains body fluid composition, like urine, bile, or sweat, despite incorporation into body

structures (bones/other tissues) or losses from the body

In Summary:

What is the digestive systems role in homeostasis?

Examples:

How Does the Digestive System Help Maintain Homeostasis?

Nutrient Absorption

Regulation

Energy Regulation

pH Regulation

Body Fluid Regulation

Elisabeth Ormandy, 2020.

Common Digestive Diseases

Gastroesophageal reflux disease (GERD): GERD is the

main cause of the symptom commonly known as

heartburn. When the lower esophageal sphincter isn't

functioning properly, stomach contents back up (or reflux)

into the esophagus. It's a very common condition, marked

by a burning sensation in the upper abdomen, usually

after eating.

Peptic ulcers: A peptic ulcer is an erosion of the lining of

the stomach or duodenum caused by stomach acid and

pepsin (a digestive enzyme). Symptoms can include

bleeding, gastric obstruction and in some cases, life-

threatening perforation. Most peptic ulcers are caused by

a Helicobacter pylori (H. pylori) infection.

Gastritis: Gastritis is an inflammation of the stomach

lining with symptoms similar to heartburn. It's usually

treated with medication to reduce stomach acid.

Gastroparesis: Also referred to as delayed gastric

emptying, gastroparesis is a disorder in which the

stomach takes too long to empty its contents, usually

caused by damage to the stomach nerves.

Gallstones: Gallstones can form in the gallbladder when

bile hardens. When gallstones block the cystic duct of the

gallbladder, you may feel severe pain.

Celiac disease: People who have celiac disease can't eat

gluten since it damages the small intestine. This is a

condition you would need to have diagnosed by a

healthcare provider, and it's often mistaken for other

gastrointestinal disorders before being recognized.

Diverticular disease: Diverticulitis is the inflammation of

diverticula, which are protrusions in the walls of the

intestines. The presence of these sacs is known as

diverticulosis. Most people with diverticulosis may never

experience symptoms. Diverticulitis, on the other hand,

produces sharp pains in the lower left abdomen, usually

accompanied by a fever. If you suspect diverticulitis, see a

healthcare provider as soon as you can. If left untreated,

diverticulitis can cause life-threatening complications.

Inflammatory bowel disease: This is an umbrella term for

two separate conditions: ulcerative colitis and Crohn's

disease. Both are chronic conditions that require lifelong

monitoring and treatment.

Irritable bowel syndrome (IBS): People dealing with this

very common digestive disorder have recurring abdominal

pain, and either diarrhea, constipation or both.

Elisabeth Ormandy, 2020.

Were you able to successfully learn the structure and function of individual parts of the digestive

system?

How might virtual dissections and models compare with using real specimens?

What is one way the digestive system maintains homeostasis within the body?

What is one way the digestive system interacts with other body systems?

What are the main structures food moves through within the digestive system?

During the check closing in:

Recap with the students the path food moves through within the digestive system. Go over ways the

digestive system interacts with other body systems, as well as how it helps maintain homeostasis. Ask

the following questions:

Closing - Discussion on Ethics

The knowledge to create these accurate virtual models of the digestive system had to initially come

from real humans and or animals. However, now that we have such a plentiful resources for accurate

models of these structures, as well as the ability to perform dissections virtually, do you think we need

to continue using animals? Why or Why not?

Think

Ask the students to think about where they stand on the subject of animal dissections and the use of

animals in science. They don't need to answer right away, rather, this is to get them to start forming

their own ethical opinions and will be discussed later on in the unit.

Formative Assessment

The formative assessment can be in the form of an exit slip. This involves asking each student at the

end of the class to answer 2-3 questions on a sheet of paper and hand it in, with their names on it, to

ensure understanding of the main concepts covered. Examples of questions to include:

Closing Check-In and Discussion

Elisabeth Ormandy, 2020.

Thank you for choosing these materials to support your class adventures!

These Humane Science Education materials were developed by Elisabeth

Ormandy for the Canadian Society for Humane Science (2015-2022) working to

achieve better science without animals. By choosing these unit plans, you have

joined a growing family of Humane Science Educators!

We gratefully acknowledge the support of the following funders of

this Humane Science Education Program: